the clock it seems most contractors base their time frames on that although looking like a regular clock moves at only half the time. Thus if they start at 9AM universal and say it will take 4 hours, the real time they are done 5pm. However it is only used for work time, not billable hours.

the bathroom guy got here at 10AM and said it would take 3 hours he didn't leave until 4PM
he must have been using a contractor clock